During an immune response to invading pathogen or to tumorigenesis inflammation is essential for combating pathogens. However, inflammation is also closely associated with a number of age-associated diseases. We have demonstrated that transcription factors T cell factor (TCF)-1 and beta-catenin together positively regulate T cell function by inducing the expression cytokines such as IL-4. Whereas TCF1 alone negatively regulates the expression of a number of pro-inflammatory cytokines. Thus, these transcription factors have the potential to positively and negatively regulate immune function and inflammation. We have initiated studies to delineate mechanisms by these transcription factors perform these function in-vivo. To determine the role of TCF-1 and beta-catenin in cytokine production and immune response in aged mice we will compare these functions in young and old mutant mice.